Why metal and glass are demanding surfaces
Metal cans, aluminum foil lidding, and glass bottles are hard, smooth, and completely non-porous. There is nothing for ink to soak into, so the code has to bond to the surface itself. Water-based inks bead and wipe off; you need a solvent-based ink whose resin grips a sealed surface and sets fast.
These surfaces are also often curved and can carry a film of oil, dust, or condensation from upstream processes — all of which fight adhesion if you do not account for them.
Choose a fast-setting solvent ink
Solvent-based thermal inkjet inks are the default for metal and glass: they flash off quickly and leave a durable, smudge-resistant mark. For especially demanding adhesion or downstream washdown, a specialty ink may be warranted — tell us the exact process and we will match it.
- Solvent ink for fast set and adhesion on non-porous metal, foil, and glass
- Confirm the cured code passes a tape and thumb-rub test on your actual part
- For washdown or retort processes, ask about a specialty durable ink
Surface prep and handling
Adhesion on smooth surfaces is only as good as the surface you print on. A clean, dry code zone makes the difference between a mark that lasts and one that scratches off.
- Print on a clean, dry surface — knock down oil, dust, and condensation in the code zone
- Keep the printhead close: metal and glass are near-contact, and throw distance blurs the code
- Stabilize curved parts (cans, bottles) so the surface passes the head smoothly
Where thermal inkjet fits
With the right solvent ink and a clean surface, thermal inkjet codes metal and glass cleanly and at high resolution — dates, lot codes, and barcodes — with the low maintenance of sealed cartridges. Send us your substrate (and whether it faces washdown or heat) and we will qualify an ink with you.